The present invention pertains to a portable motorized chain saw and more particularly to a portable motorized chain saw having a clutch which is arranged between the motor drive shaft and the chain sprocket and wherein a brake band acts on a drum which is adjacent to the chain sprocket.
In the case of motorized chain saws of this type, the chain runs over a guide bar, which is in the same plane as the chain sprocket and, in order to keep friction and wear as small as possible, the chain is constantly lubricated, often by applying drops of oil. This lubrication of the chain necessarily contributes to better adhesion of sawn particles, i.e., saw dust, chips and the like on the chain. Therefore, when considering the small constructional proportions in relation to justifiable expenses, it is practially unavoidable that dirt and oil are thrown out, especially in the area of the sharp change in direction of the chain which occurs at the chain sprocket. In this manner, oil particles, in particular, but also dirt particles reach the area of the contact surface of the brake band on the drum of the clutch, as a result of which the braking effect and thus also the safety of the saw is deleteriously influenced in emergency situations.